The inventive concept relates to a method of operating a data storage device, the data storage device, and a system using the data storage device.
Generally, a semiconductor memory device is a memory device that is implemented using a semiconductor material, such as silicon (Si), germanium (Ge), gallium arsenide (GaAs), or indium phosphide (InP). Semiconductor memory devices are broadly classified as volatile memory devices and nonvolatile memory devices.
Volatile memory devices lose stored data when the power supply is turned off. Examples of the volatile memory devices include static random access memories (SRAMs), dynamic random access memories (DRAMs), and synchronous dynamic random access memories (SDRAMs). In contrast, nonvolatile memory devices retain stored data even when the power supply is turned off or otherwise interrupted. Examples of the nonvolatile memory devices include flash memories, read-only memories (ROMs), programmable read-only memories (PROMs), erasable programmable read-only memories (EPROMs), electrically erasable programmable read-only memories (EEPROMs), and resistive memories (e.g., phase-change random access memories (PRAMs), ferroelectric random access memories (FRAMs), and resistive random access memories (RRAMs)).
In a flash memory, in particular, the threshold voltage of a memory cell corresponding to an upper portion of an erase state distribution tends to be shifted toward a program state distribution due to coupling with adjacent cells, a disturbance, or the like. The memory cell is therefore likely to have an error.